function initMap() {
    // The location of Uluru
    var myLatlng = new google.maps.LatLng(31.281966, 121.212019);
    // The map, centered at Uluru
    let mapOptions = {
        zoom: 22,
        center: myLatlng,
        mapTypeId: 'satellite'
    };
    let map = new google.maps.Map(document.getElementById('googlemap'), mapOptions);
    // The marker, positioned at Uluru
    let marker = new google.maps.Marker({position: myLatlng, map: map});
}